Designation C709 − 09 An American National Standard Standard Terminology Relating to Manufactured Carbon and Graphite1 This standard is issued under the fixed designation C709; the number immediately[.]
Trang 1Designation: C709−09 An American National Standard
Standard Terminology Relating to
This standard is issued under the fixed designation C709; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
across (or against) grain, n—direction in a body with
pre-ferred orientation due to forming stresses that has the
maximum c-axis alignment as measured in an X-ray
diffrac-tion test
agglomerate, n— in manufactured carbon and graphite
prod-uct technology, composite particle containing a number of
grains
anistropic nuclear graphite, n—graphite in which the
isot-ropy ratio based on the value of the coefficient of thermal
expansion (25–500°C) is greater than 1.15
ash, n—in carbon and graphite technology, residue remaining
after oxidation of a carbon or graphite
binder, n—substance, usually an organic material such as coal
tar pitch or petroleum pitch, used to bond the coke or other
filler material prior to baking
carbon, n—element, number 6 of the periodic table of
elements, electronic ground state 1s22s22p2
carbon, n—in carbon and graphite technology, artifact
con-sisting predominantly of the element carbon and possessing
limited long range order
D ISCUSSION —The presence of limited long range order is usually
associated with low electrical and thermal conductivity and difficult
machinability when compared with graphite.
carbon foam, n— in carbon and graphite technology, porous
carbon product containing regularly shaped, predominantly
concave, homogeneously dispersed cells which interact to
form a three-dimensional array throughout a continuum
material of carbon, predominantly in the non-graphitic state
The final result is either an open or closed cell product
D ISCUSSION —In most foam, the cell wall thickness is less than half
the average cell size.
cell (bubble), n—in carbon and graphite technology, single
small cavity formed by gaseous displacement in a precursor
material in its plastic state, and surrounded completely by its walls when formed Cells can be open or closed
D ISCUSSION —After processing at high temperatures, the basic struc-ture of the cell will remain even as the material converts from a plastic state to a rigid carbonaceous structure Hence, the term cell will apply
to a carbon product.
cell count, n—in carbon and graphite technology, in
closed-cell foams, number of closed-cells aligned in one plane in one linear
inch, as determined by stereoscopic image analysis
cell size, n—in carbon and graphite technology, average
diameter of the cells in the final foam product
closed cell, n— in carbon and graphite technology, cell totally
enclosed by its walls and hence not interconnected with other cells A closed cell foam is a foam consisting predomi-nantly of closed cells
coke, n—carbonaceous solid produced from coal, petroleum,
or other materials by thermal decomposition with passage through a plastic state
compressive strength, n—property of solid material that
indicates its ability to withstand a uniaxial compressive load
defect, n—of a manufactured carbon or graphite product, any
irregularity in the chemistry, microstructure, or macrostruc-ture
defective, adj—having flaws or dimensional deviations greater
than acceptable for the intended use
electrographite, n—in carbon and graphite technology,
syn-onym for manufactured graphite
extruded, v—formed by being forced through a shaping orifice
as a continuous body
filler, n—in manufactured carbon and graphite product
technology, carbonaceous particles comprising the base
aggregate in an unbaked green-mix formulation
flaw, n—defect sufficiently greater than those typical of the
morphology of a carbon or graphite body to influence a property
flexural strength, n—property of solid material that indicates
its ability to withstand a flexural or transverse load
1 This terminology is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.F0 on Manufactured Carbon and Graphite Products.
Current edition approved Dec 1, 2009 Published January 2010 Originally
approved in 1972 Last previous edition approved in 2006 as C709–06 DOI:
10.1520/C0709-09.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 United States
Trang 2flow line, n—defect induced by discontinuous flow velocities
during forming of molded or extruded bodies
grade, n—designation given a material by a manufacturer such
that it is always reproduced to the same specifications
established by the manufacturer
grain, n—in manufactured (synthetic) carbon and graphite,
particle of filler material (usually coke or graphite) in the
starting mix formulation Also referred to as granular
material, filler particle, or aggregate material The term is
also used to describe the general texture of a carbon or
graphite body, as in the descriptions listed below:
coarse grained, adj—containing grains in the starting mix
that are substantially greater than 4 mm in size
fine grained, adj—containing grains in the starting mix that
are generally less than 100 µm in size
medium grained, adj—containing grains in the starting mix
that are generally less than 4 mm in size
microfine grained, adj—containing grains in the starting mix
that are generally less than 2 µm in size
superfine grained, adj—containing grains in the starting mix
that are generally less than 50 µm in size
ultrafine grained, adj—containing grains in the starting mix
that are generally less than 10 µm in size
D ISCUSSION —All of the above descriptions relate to the generally
accepted practice of measuring the sizing fractions with a criterion that
90 % of the grains will pass through the stated screen size in a standard
particle sizing test.
graphene layer, n—in carbon and graphite technology, single
carbon layer of the graphite structure, describing its nature
by analogy to a polycyclic aromatic hydrocarbon of
quasi-infinite size
D ISCUSSION —The term graphite designates a modification of the
chemical element carbon in which planar sheets of carbon atoms, each
atom bound to three neighbors in a honeycomb-like structure, are
stacked in a three dimensional regular order For a single layer, it is not
correct to use the term graphite, which implies a three dimensional
structure.
graphite, n—allotropic crystalline form of the element carbon,
occurring as a mineral, commonly consisting of a hexagonal
array of carbon atoms (space group P 63/mmc) but also
known in a rhombohedral form (space group R 3m)
graphite, n—in carbon and graphite technology, material
consisting predominantly of the element carbon and
possess-ing extensive long-range three-dimensional crystallographic
order as determined by X-ray diffraction studies
D ISCUSSION —The presence of long-range order is usually
accompa-nied with high electrical and thermal conductivity within the hexagonal
plane This results in a material having relatively easy machinability
when compared to non-graphitic materials The use of the term
graphite without reporting confirmation of long-range crystallographic
order should be avoided as it can be misleading.
graphite foam, n—in carbon and graphite technology, porous
graphite product containing regularly shaped, predominantly
concave, homogeneously dispersed cells which interact to
form a three-dimensional array throughout a continuum
material of carbon, predominantly in the graphitic state The final result is either an open or closed cell product
D ISCUSSION —In most foam, the cell wall thickness is less than half the average cell size.
graphitic, adj— in carbon and graphite technology, all
vari-eties of substances consisting predominantly of the element carbon in the allotropic form of graphite irrespective of the presence of structural defects
D ISCUSSION —The use of the term graphitic is justified if three-dimensional hexagonal crystalline long-range order can be detected in the material by X-ray diffraction methods, independent of the volume fraction and the homogeneity of distribution of such crystalline domains Otherwise, the term non-graphitic should be used.
graphitizable carbon, n—in carbon and graphite technology,
non-graphitic carbon, which, upon graphitization, converts into graphitic carbon (also known as a soft carbon)
graphitization, n—in carbon and graphite technology,
solid-state transformation of thermodynamically unstable non-graphitic carbon into graphite by thermal treatment
D ISCUSSION —The degree of graphitization is a measure of the extent
of long-range 3D crystallographic order as determined by diffraction studies only The degree of graphitization affects many properties significantly, such as thermal conductivity, electrical conductivity, strength, and stiffness.
D ISCUSSION —A common, but incorrect, use of the term graphitization
is to indicate a process of thermal treatment of carbon materials at T > 2200°C regardless of any resultant crystallinity The use of the term graphitization without reporting confirmation of long range three dimensional crystallographic order determined by diffraction studies should be avoided, as it can be misleading.
graphitizing (nuclear grade) isotropic/near-isotropic coke—a coke, which under reflected light microscopy,
shows a fine mosaic texture where the individual micro-scopic domains show optical activity as the stage is rotated when both the polarizer and analyzer are in a crossed position in the optical path of the microscope
D ISCUSSION —The isotropic coke with optical domains of ~20 micons
is, crucially, a coke that develops three-dimensional order on heat treatment to temperatures >2400°C, and hence may be described as graphitic Furthermore, graphite produced from such a coke exhibits a CTE in the range of 3.5 × 10 e-6 to 5.5 × 10 e-6 (25 to 500°C), and is isotropic in the sense that the ratio of the ag/wg CTE (25 to 500°C) is yielding between 1.00 and 1.10 Similarly, graphite produced from a near-isotropic coke is defined as yielding graphite wehre the ag/wg CTE (25 to 500°C) is between 1.10 and 1.15 The precursors to a graphitizing isotropic coke form fluid mesophase on thermal conver-sion to a solid graphitizable carbon.
green carbon, n—formed, but unfired carbon body.
hard carbon, n—see non-graphitizable carbon.
hardness, n—resistance of a material to deformation,
particu-larly permanent deformation, indentation, or scratching
impervious carbon, n—same as impervious graphite with the
exception that the base stock has not been graphitized
impervious graphite, n—manufactured graphite that has been
impregnated with a resinous material to make the final article impervious to liquids in the recommended operating range
Trang 3impregnation, n—partial filling of the open pore structure with
another material
isotropic, adj— in carbon and graphite technology, having an
isotropy ratio of 0.9 to 1.1 for a specific property of interest
isotropic nuclear graphite, n—graphite in which the isotropy
ratio based on the coefficient of thermal expansion
(25–500°C) is 1.00–1.10
isotropy ratio, n—in carbon and graphite technology, ratio of
a given property value in the against grain direction to its
corresponding value in the with grain direction (for example,
the ratio of coefficients of thermal expansion)
lamination, n—line of demarcation or elongated void
gener-ally parallel to the principal grain direction of a carbon or
graphite body
longitudinal sonic pulse, n—sonic pulse in which the
dis-placements are in the direction of propagation of the pulse
machinability, n—measure of the ease with which a material
can be shaped with the aid of cutting or abrasive tools
manufactured carbon, n—bonded granular carbon body
whose matrix has been subjected to a temperature typically
between 900 and 2400°C
manufactured graphite, n—bonded granular carbon body
whose matrix has been subjected to a temperature typically
in excess of 2400°C and whose matrix is thermally stable
below that temperature
molded, v—formed in a closed die by the application of
external pressure
natural graphite, n—in carbon and graphite technology,
material consisting predominantly of graphitic carbon,
which forms in the earth’s crust as the result of igneous or
metamorphic processes acting on carbonaceous materials
D ISCUSSION —The degree of crystalline perfection in these materials
may vary Natural graphite may contain significant quantities of gangue
materials, either attached to or intercalated with graphitic carbon.
near–isotropic nuclear graphite, n—graphite in which the
isotropy based on the coefficient of thermal expansion
(25–500°C) is 1.10–1.15
non-graphitizable carbon, n—in carbon and graphite
technology, carbon which cannot be transformed into
gra-phitic carbon solely by heat treatment up to 3000°C under
inert atmosphere or reduced pressure (also known as a hard
carbon)
non-graphitizing isotropic coke—a coke, which under
re-flected light microscopy shows no mosiac texture and no
optical activity when both the polarizer and analyzer are in
a crossed position in the optical path of the microscope as the
stage is rotated
D ISCUSSION —The optically inactive isotropic coke is a coke that does
not develop three-dimensional order on heat treatment to temperatures
>2400°C, and hence may not be described as graphitic The precursors
to a non-graphitizing isotropic coke do not form fluid mesophase on
thermal conversion to a solid carbon (There is the exceptional case of anthracite coal which is graphitizable but does not pass through a fluid mesophase stage.)
open cell, n—in carbon and graphite technology, cell that is
not totally enclosed in its walls and hence interconnected with other cells An open-cell foam is a foam consisting predominantly of open or connected cells
orientation (of a crystal), n—angular position of a crystal
described by the angles which certain crystallographic axes make with the frame of reference
orientation (of a grain), n—angular position of a grain
described by the angles which a defined set of axes of the grain make with the stated frame of reference Generally used to characterize the axis of the grain that has the largest physical extent, for example, in a grain of needle coke
orientation (of an object), n—angular position of an object
described by the angles which a defined set of axes or surfaces of the object make with the frame of reference
oxidation of carbon, n—chemical combination of carbon with
oxygen or oxygen-containing compounds
particle sizing, v—segregation of granular material into
speci-fied particle size ranges
penetration, n—depths to which one material extends into or
penetrates another
permeability, n—property measured by the rate of passage of
a fluid under a pressure gradient through a material
pore, n—see void.
pore, n—in carbon and graphite technology, in a carbon or
graphite foam, passage that interconnects two cells.
pore count, n—in carbon and graphite technology, in
open-cell foams, number of pores aligned in one plane in one
linear inch, as determined by stereoscopic image analysis
porosity, n—percentage of the total volume of a material
occupied by both open and closed pores
preferred orientation, n—in manufactured carbon and
graph-ite product technology, alignment in the crystal or defect
structure of a body leading to variations in physical proper-ties as a function of direction; normally referenced to an orthogonal system where one of the axes is the working direction
pulse travel time (T t), n—total time, measured in seconds,
required for the sonic pulse to traverse the specimen being tested, and for the associated electronic signals to reverse the circuits of the pulse-propogation circuitry
pyrolytic graphite, n—in carbon and graphite technology,
artifact consisting predominantly of graphite which was deposited as a solid on a hot surface by cracking of gaseous
or liquid hydrocarbons
reactivity, n—rate at which another material will form
com-pounds with carbon or graphite
Trang 4reticulated foam, n—in carbon and graphite technology, foam
with a ligamentous structure rather than a spherical pore
structure
soft carbon, n—see graphitizable carbon.
surface finish, n—geometric irregularities in the surface of a
solid material Measurement of surface finish shall not
include inherent structural irregularities unless these are the
characteristics being measured
tensile strength, n—property of solid material that indicates its
ability to withstand a uniaxial tensile load
ultimate tensile strength, n—highest load attained during a
tensile test, converted to unit stress based on the original
cross-section area of the tensile test specimen
void, n—unfilled space enclosed within an apparently solid
carbon or graphite body
with grain, n—direction in a body with preferred orientation
due to forming stresses that has the maximum a-axis
alignment as measured in an X-ray diffraction test
working direction, n—in manufactured carbon and graphite
product technology, direction of applied force used in
forming a solid body; generally the direction of applied molding pressure for a uniaxially molded material and the extrusion direction for an extruded material
zero time (T o), n—travel time (correction factor), measured in
seconds, associated with the electronic circuits in the pulse propagation system
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